PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 70-100% Life expectancy: More than 3 months Hematopoietic: Absolute neutrophil count at least 750/mm3 Platelet count at least 75,000/mm3 Hemoglobin at least 11 g/dL (10 g/dL in women) CD4 count greater than 50 cells per cubic millimeter Hepatic: Bilirubin no greater than 1.5 times normal (unless due to Gilbert's disease) Patients on protease inhibitors may have bilirubin no greater than 3.5 mg/dL (direct bilirubin no greater than 0.2 mg/dL) AST/ALT no greater than 75 IU/mL Alkaline phosphatase no greater than 2.5 times normal Renal: Creatinine less than 1.5 mg/dL Creatinine clearance (calculated) greater than 55 mL/min Proteinuria less than 2+ Cardiovascular: No significant EKG abnormality Other: No actively life-threatening infection At least 14 days since treatment for serious infection No known clinically significant allergy to probenecid or sulfa No grade 3 or worse clinical or laboratory toxicity other than lymphopenia No medical condition that precludes protocol treatment or informed consent No second malignancy within 1 year except basal cell skin cancer No pregnant or nursing women Negative pregnancy test required of fertile women within 1 week prior to entry, every 4 weeks while on study, and 4 weeks after last treatment Effective contraception required of fertile women